The disclosure relates to a method for producing a multicomponent compound, in particular for dental purposes, by pressing its components out of cartridges by means of pistons, and by mixing the components. The disclosure also relates to a device for carrying out the method.
Various problems occur in the production of multicomponent compounds, in particular for dental purposes. On the one hand, the components must be pressed in precisely the right mixture ratio into a mixer where they are mixed and can then be discharged. If the two components are to be used in equal quantities, then cylinders with equal diameter could be used as cartridges, with the pistons then also being moved forwards at the same speed in order to press out the components. This can take place by means of a single drive. With a device of said type, it would also be possible to press out components in some other ratio if the cartridges or cylinders have different diameters. A better adaptation to different mixing ratios is however obtained if each of the pistons is provided with a separate drive (DE 199 51 504 A1). In this way, it is possible to obtain the desired mixing ratio if the cartridges are actually filled and the pistons bear against the components such that no air pocket is present there. If an air pocket of said type is present in one of the cartridges, then material would of course initially be driven only out of one cartridge when both drives are set in operation, while in the other cartridge, the air would initially be compressed and escape such that no material or in any case far too little material is discharged. For this problem, too, however, there is a solution which is disclosed and claimed in a patent application filed at the same time as the present application.
In all of said cases, however, the following problem always occurs. When the piston is pressed against the material, an abrupt pressure increase takes place. This is the case in particular when the piston is moved with increased speed for as long as there is still air present between the piston and the material which is to be dispensed. A result of this is that, at the start, the desired mixing ratio is not obtained.
An object is that of creating a method and a device of the type specified in the introduction, in which, even in cases in which the piston is initially moved with high speed, pressing out under an initially increased pressure is prevented.
A solution comprises that the pressing-out process, at the beginning thereof, takes place at a reduced pressure.